ing. But in the more recent period, the declines in mortalilty from a non-infectious or degenerative type of diseases have become much more important in contributing to a lengthening of life expectancy. Hence, the lengthening of life expectacy itself lately joins in contributing to accelerate the population ageing in Japan which is principally caused by fertility decline.
G. Fertility Decline and Its Determinants in Japan
It was already mentioned that fertility has declined to an unprecedentedly low level in recent years, much lower than the net replacement level.Since the fertility decline has been the most important determinant factorin causing the population ageing of Japan and since in recent years the issue of fertility decline has evoked great interest and concern among the government workers, industrialists as well as intellectuals, a few words must be devoted here to explain why the current Japanese fertility has precipitated to so low a level and how far the trend would continue in the near future.
On the basis of the vital statistics collected by the Ministry of Health and Welfare, the total fertility rate in Japan has been lower than the replacement level since 1974 (See Table 4). The recent movement is, however, unprecedented and beyond our previous experience and projections. In 1990,it went down to 1.53. In 1994 it went up slightly to 1.50, but in 1995 it was reduced to 1.43, the lowest ever recorded in Japan. Alarmed by this fertility plunge, many different groups of people, industrialists, parliamen tarians or high ranking government officials expressed their concern and worries that the continuation of such a low rate would give enormous adverse impacts on the Japanese economy and society. According to one series of calculations tentatively prepared by the present author, if the current low total fertility were to continue and the same life expectancies as observed in 1990 were to be kept constant for future years, the population of Japan must get extinct in less than 800 years' time. Such a calculation is of course a kind of science fiction, but it has striked out some demographic implications. And even before such a tragic state of affairs would have ever come true, it has been argued strongly that Japan will inevitably face the exceedingly advanced population ageing or a very large percentage of the aged which may amount to one-fourth or even to one-third of the total population in Japan. If such an extraordinary population ageing has ever come to the seashore of Japan, it has been argued that Japan would collapse under the heavy dependence burden of the elderly, whereas the segment
